Langmuir, Vol.25, No.14, 7828-7835, 2009
Self-Assembled Monolayers of Bisphosphonates: Influence of Side Chain Steric Hindrance
Bisphosphonates form self-assembled monolayers (SAMs) spontaneously on stainless steel, silicon, and titanium oxidized surfaces. We used contact angle measurements, atomic force microscopy, and X-ray reflectivity analysis to study the formation of SAMs on a model surface of ultraflat titanium (rms = 0.2 nm), The results were extended to standard materials (mechanically polished titanium, stainless steel, and silicon) and showed that water-soluble bisphosphonic perfluoropolyether can easily form SAMs, with 100% surface coverage and a layer thickness of less than 3 rim. Hydrophobic (water contact angle > 110 degrees on stainless steel or titanium) and lipophobic (methylene iodide contact angle > 105 degrees on titanium) properties are discussed in terms of industrial applications.